The Session Initiation Protocol (SIP) Extension for Event State Publication describes a mechanism with which a presence user agent is able to publish presence information to a presence agent. Using the Presence Information Data Format (PIDF)@ each presence publication contains full state@ regardless of how much of that information has actually changed since the previous update. As a consequence@ updating a sizeable presence document with small changes bears a considerable overhead and is therefore inefficient. Especially with low bandwidth and high latency links@ this can constitute a considerable burden to the system. This memo defines a solution that aids in reducing the impact of those constraints and increases transport efficiency by introducing a mechanism that allows for publication of partial presence information.
RFC 5264-2008 history
2008RFC 5264-2008 Publication of Partial Presence Information